Dust-proof headlight assembly



June 13, 1967 SOICHIRO HONDA 3,325,637

DUST-PROOF HEADLIGHT ASSEMBLY Filed Dec. 9, 1964 Z'Sheets-Sheet l INVENTOR ATTORNEYS June 13, 1967 SOICHIRO HONDA 3,325,637

DUST-PROOF HEADLIGHT ASSEMBLY 7 Filed Dec. 9, 1964 2 Sheets-Sheets INVENTOR SWM ATTORNEYJ United States Patent 3,325,637 DUST-PROOF HEADLIGHT ASSEMBLY Soichiro Honda, Shinjuku-ku, Tokyo, Japan, assignor to Kabushiki Kaisha Honda Gijutsu Kenlryusho, Saitarnaken, Japan, a corporation of Japan Filed Dec. 9, 1964, Ser. No. 417,196 Claims priority, application Japan, Mar. 14, 1964, 39/ 14,194 Claims. (Cl. 2407.1)

The present invention relates to an improvement in an apparatus, chiefly such a lamp as a headlight or the like, attached to vehicles such as motorcars, motorcycles or the like, for preventing the front transparent plate of the lamp from becoming dirty or dim due to the accumulation of dust.

According to the present invention, there is provided such an apparatus as above described characterized in that a light source is provided within a casing which is usually reflecting, and a transparent plate is attached to the front surface of the casing to form a lamp housing of which the interior is sealed as tightly as possible against the exterior air, and the interior of the housing is in communication with a separate tightly sealed resiliently distendable air chamber which is expandable and contractable to a large extent and is positioned substantially spaced and remote from the lamp housing, so that the expansion and contraction of the air within the housing due to change in temperature, can be taken up by the tightly sealed expandable air chamber and heat from the lamp does not pass by direct conduction to the chamber.

Several embodiments of the present invention will be described with reference to the accompanying drawings in which,

FIG. 1 is a side View, partly in section of one embodiment of the present invention;

FIGS. 2 and 3 are side sectional views of other modified forms of the same; and

FIG. 4 is a sectional side view of a modified diaphragm form of a tightly sealed air chamber.

Referring to FIG. 1, a casing 1 of which the inner surface is a reflecting surface to constitute a reflector, has therein as a light source 2 an electric light bulb, and a transparent plate 3 constituting a lens is applied to the front surface of the casing 1 and is tightly connected thereto at a rim 7 through a dustproof resilient ring packing 6 of such material as rubber or the like, whereby there is formed a lamp housing A of which the interior is sealed as tightly as possible. The housing A is attached to the front end of a car body 8 so that its greater portion is embedded therein.

The casing 1 has a stub connection 9 projecting therefrom and the stub 9 is attached through a flexible pipe or tube 5 leading to a separate tightly sealed resilient air chamber 4 of a bag shaped like a balloon, which is expandable and contractable so that it can become large enough to absorb the expansion and contraction of the air within the housing A when the light is turned on and off. Chamber 4 is positioned substantially spaced and remote from the lamp housing. Thus, the interior of the housing A is in communication with the interior of the tightly sealed resilient air chamber 4. Numeral 10 denotes a source as a power line connection.

FIG. 2 shows another form of the present invention in which an electric light bulb 12 is mounted within a reflector plate 11, and a transparent plate 13 constituting a lens is attached to the front surface of the reflector, whereby there is formed a so-called sealed beam type lamp unit of which the interior is completely airtight. Inner housing 16 comprises transparent plate 13 and reflector plate 11. The power supply line 10b is connected to terminal 10a of light bulb 12. This lamp unit is mounted as a light source within a member 17 attached to the front end of a car body 8, and a transparent cover plate 18 is applied to the front surface of the member 17 and is connected tightly thereto at a rim 7 through a dustproof ring packing 6 so that there is formed a lamp housing D of which the interior is sealed as tightly as possible against the exterior air and constitutes the sealed beam lamp unit. The interior of the housing D is in communication with separate tightly sealed resilient air chamber 4 which is expandable and contractable through a flexible tube 5 attached to an attaching connection stub 9 projecting from the casing 17.

FIG. 3 shows further another modification of the present invention, in which an inner housing B comprising a casing 1, an electric light bulb 2 and a front transparent plate 19, is provided as a light source mounted within a casing 14, and a transparent plate 15 is connected to the front surface of the casing to form an outer housing C. These inner and outer housings B and C are both separately in communication with a separate tightly sealed resilient air chamber 4 which is expandable and contractable through respective flexible tubes 5a and 5b, so that the expansion and contraction of the air within the two housings B and C owing to the rise and fall of the temperature when the light is turned on and off, can be absorbed by the expansion and contraction of the air chamber 4. Chamber 4 is positioned substantially spaced and remote from the outer lamp housing. In FIG. 3, numeral 6 is a dustproof ring packing, numeral 7 is a rim, numerals 9a and 9b are respective attaching stub connections projecting from each of the casings 1 and 14 for attaching the flexible tubes 5a and 5b thereto. 10b is a power supply connection to terminal 10a of light bulb 2.

The tightly sealed resilient air chamber 4 shown in FIGS 1 to 3 is of a bag shaped like a balloon made of flexible film or sheet of such materials as rubber, soft synthetic resin or the like, but the same may be modified to be of diaphragm type as shown in FIG. 4, having a diaphragm 20.

In a lamp of such construction that a light source is provided within a casing and a transparent plate is attached to the front surface thereof, it often happens that as a result of its use, the inner surface of the front transparent plate becomes dirty or dim, which lowers the intensity of illumination. This is based on the fact that in accordance with the rise and fall of the interior temperature on the occasion of switching the light on and off, large expansion and contraction of air is caused repeatedly to cause the change in air pressure within the housing, and as a result thereof, the exterior air invades the housing through the unsealed connecting portion between the casing and the transparent plate or other portion, and accompanying the same the air containing dust or high in humidity enters therein. However, for the purpose of the replacement of the interior light source such as a burned out electric light bulb, or the adjustment of the position of the light source or other purposes, it is essential in the prior art, that the transparent plate be formed to be of separable construction. Therefore, in the prior art, it is usual that there still exists more or less outside air even if the interior is sealed as tightly as possible against the exterior air, and no absolute air tightness can be obtained. Accordingly, it is impossible to prevent completely the dirtiness and dimness of the front plate owing to the entry of the exterior air as mentioned before.

According to the present invention, however, in a housing which is sealed as tightly as possible against the exterior air, the interior thereof is in communication with a separate tightly sealed resilient air chamber which is expandable and contractable and is positioned substantially spaced and remote from the housing. Accordingly, if the resilient air chamber is so designed that the same easily absorbs the difference in volume of the air within the housing owing to its ready expansion and contraction, the air pressure within the housing can be always kept nearly constant, and the inflow and outflow of the exterior air owing to an extremely small passage in the housing can be prevented almost completely, whereby the above mentioned defects of dust accumulation can be avoided.

I claim:

1. In a dust-proof lamp assembly, enclosing means comprising a first curvilinear reflecting member, transparent front plate means closing the aperture in said reflecting member and being tightly sealed thereto, a separate resilient air expansion chamber positioned substantially spaced and remote from said enclosing means, and air connection means connecting the interior of said enclosing means to said chamber.

2. In a dust-proof lamp assembly, an open casing, a transparent front plate closing said casing and being tightly sealed thereto, an electric lamp mounted in said casing, a separate resilient air expansion chamber positioned substantially spaced and remote from said casing, and air connection means connecting the interior of said casing to said chamber.

3. In a dust-proof lamp assembly, an open casing, a

transparent front plate closing said casing and being tightly sealed thereto, an electric lamp mounted in said casing, a separate resilient air expansion chamber positioned substantially spaced and remote from said casing, and an outer box enclosing said casing and said front plate and comprising a wall member extending rearwardly of said casing and surrounding the same, and a transparent cover plate member tightly sealed to said wall member, and primary air connection means connecting the space enclosed by said wall member and said cover plate to said chamber.

4. In a dust-proof headlight assembly, an open casing, a transparent front plate closing said casing and being tightly sealed thereto, an electric lamp mounted in said casing, a resilient air expansion chamber, and an outer box enclosing said casing and said front plate and comprising a wall member extending rearwardly of said casing and surrounding the same, and a transparent cover plate member tightly sealed to said wall member, and primary air connection means connecting the space enclosed by said wall member and said cover plate to said chamber, and secondary separate connecting means connecting the space enclosed by said casing and said front plate to said chamber.

5. An assembly according to claim 2, said chamber comprising a resilient diaphragm.

References Cited UNITED STATES PATENTS 10/1926 Amidon 24041.6 6/1965 Trautner et a1 2404l.55 

